Pharmacokinetics and Metabolism of Delamanid, a Novel Anti-Tuberculosis Drug, in Animals and Humans: Importance of Albumin Metabolism In Vivo
作者:Katsunori Sasahara、Yoshihiko Shimokawa、Yukihiro Hirao、Noriyuki Koyama、Kazuyoshi Kitano、Masakazu Shibata、Ken Umehara
DOI:10.1124/dmd.115.064527
日期:2015.8
Delamanid, a new anti-tuberculosis drug, is metabolized to M1, a unique metabolite formed by cleavage of the 6-nitro-2,3-dihydroimidazo[2,1- b ] oxazole moiety, in plasma albumin in vitro. The metabolic activities in dogs and humans are higher than those in rodents. In this study, we characterized the pharmacokinetics and metabolism of delamanid in animals and humans. Eight metabolites (M1–M8) produced by cleavage of the imidazooxazole moiety of delamanid were identified in the plasma after repeated oral administration by liquid chromatography–mass spectrometry analysis. Delamanid was initially catalyzed to M1 and subsequently metabolized by three separate pathways, which suggested that M1 is a crucial starting point. The major pathway in humans was hydroxylation of the oxazole moiety of M1 to form M2 and then successive oxidation to the ketone form (M3) mainly by CYP3A4. M1 had the highest exposure among the eight metabolites after repeated oral dosing in humans, which indicated that M1 was the major metabolite. The overall metabolism of delamanid was qualitatively similar across nonclinical species and humans but was quantitatively different among the species. After repeated administration, the metabolites had much higher concentrations in dogs and humans than in rodents. The in vitro metabolic activity of albumin on delamanid probably caused the species differences observed. We determined that albumin metabolism is a key component of the pharmacokinetics and metabolism of delamanid. Nonhepatic formation of M1 and multiple separate pathways for metabolism of M1 suggest that clinically significant drug–drug interactions with delamanid and M1 are limited.
德拉马尼是一种新型抗结核药物,在体外血浆白蛋白中被代谢为M1,这是一种通过切割6-硝基-2,3-二氢咪唑并[2,1-b]恶唑部分形成的独特代谢物。狗和人类的代谢活性高于啮齿动物。本研究对动物和人体内德拉马尼的药代动力学和代谢进行了特征分析。通过液相色谱-质谱分析,在反复口服给药后,在血浆中鉴定出由德拉马尼的咪唑并恶唑部分切割产生的八种代谢物(M1-M8)。德拉马尼最初被催化成M1,然后通过三条单独的途径进行代谢,这表明M1是一个关键的起始点。人类主要的代谢途径是对M1的恶唑部分进行羟化形成M2,然后主要由CYP3A4连续氧化成酮形式(M3)。在反复口服给药后,M1在八种代谢物中的暴露量最高,这表明M1是主要的代谢产物。德拉马尼的整体代谢在非临床物种和人类中在定性上相似,但在物种之间在定量上有所不同。反复给药后,狗和人体内的代谢物浓度远高于啮齿动物。白蛋白对德拉马尼的体外代谢活性可能是观察到的物种差异的原因。我们确定白蛋白代谢是德拉马尼药代动力学和代谢的关键组成部分。非肝脏形成M1和多条单独的代谢途径表明,德拉马尼和M1的临床显著药物-药物相互作用有限。